ÃÛÌÒTV

Event details

Title: Modelling turbulence in neutron stars

Abstract: Insufficient numerical resolution of grid-based, direct numerical simulations (DNS) hampers the development of instability-driven turbulence at small (unresolved) scales. As an alternative to DNS, sub-grid models can potentially reproduce the effects of turbulence at small scales in terms of the resolved scales. They, hence, can capture physical effects with fewer computational resources. In this talk, I will present the MHD-instability-induced-turbulence (MInIT) mean-field model, which is based on the evolution of the turbulent kinetic energy density. I will talk about its application to the Kelvin-Helmholtz instability, which is present during the merger of two neutron stars. I will also show its application to the magnetorotational instability (MRI), which plays a role during the neutron star postmerger phase and during the formation of protoneutron stars. The effects produced by small-scale turbulence can impact the neutron star's stability and its consequent gravitational wave emission. Moreover, I will also talk about a new effective model for the saturation amplitude of the MRI, which is based on a careful treatment of the parasitic instabilities, which are responsible for the saturation.

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